This invention relates to a reservoir type water heating device serving as a source of hot water supply used with a central hot water supply system or a small-sized central hot water system and more particularly to such a device employing a combustion device as a heating source and especially including an exhaust pipe for exhaust gases generated by the combustion.
In central hot water supply systems or small-sized simple hot water supply systems (which supply hot water to the bath, kitchen, washing stand etc. which are used in a single house), the heating source therefor is made up of a reservoir type water heating device adapted to be heated by a combustion device. It has been found that in a water heating device of the type referred to and which includes the exhaust pipe through which exhaust gases resulting from the combustion effected by an associated combustion device are exhausted outside thereof, and particularly in which petroleum products such as, for example, kerosene is used as a fuel, it has been found that frequently, a gun type burner is used.
In conventional reservoir type water heating devices which include a gun type burner, the drum serving as a hot water reservoir has a combustion chamber underneath a heat transfer wall and the burner establish a flame within the combustion chamber to heat water in the drum. A flue is made of a heat transfer material and communicates with the combustion chamber and extends centrally through the drum to exhaust gaseous combustion products to the atmosphere. After the flame is automatically cut-off in the combustion chamber due to the water in the drum reacting a predetermined temperature, heat accumulated in the water dissipates from the heat transfer wall and flue to the atmosphere through spontaneous convection. Accordingly, the greater the amount of hot water accumulated in the drum the greater a quantity of dissipated heat will result in the undesirable problem that the operation efficiency decreases. In view of applicants' experience, it is believed that this problem has not been noticed by experts in the field and therefore no measures to solve the problem have been taken.